Abstract
Purpose :
Diabetic patients have a wider range of cone densities than controls and have capillary remodeling on AOSLO, even with normal total retinal thickness on OCT. To probe the relation of retinal vs. subretinal changes to cone distribution, we used OCT to localize lesions and OCTA for vessel remodeling and decreased flow.
Methods :
Cone density and retinal vessels were imaged as previously for 10 diabetic subjects (29-79 yr, 54.5 +/- 12.7 yr). All subjects were consented and tested as approved by the Indiana University Institutional Review Board, which adhered to the Declaration of Helsinki. We performed OCT and OCTA (Heidelberg Spectralis II), then imaged cones and retinal microcirculation with AOSLO, using confocal and multiply scattered light images. We used reflectance mode and motion mapping for vessels, montaging images for the 6 x 6 deg central retina and temporal retina to 7 deg. Graders assessed OCT B-scans for cysts, exudates, microaneurysms, layer disruptions, subretinal fluid, and subretinal deposits and OCTA for lower flow and vessel remodeling. A 2-parameter exponential model of cone density, ln(cone density) = a * microns eccentricity + b, estimated total cones within the central 14 deg.
Results :
Both total cones, 173,000 – 283,000, and vascular findings differed among subjects. All subjects had retinal microaneurysms and capillary remodeling seen shadowing cone maps and seen in inner retinal images on AOSLO. Retinal OCTA localized lesions in all subjects, but less capillary remodeling than AOSLO. Significant subretinal OCT or OCTA findings were not seen in either younger subject, with total cones 176,000 and 189,000, < the 95% CIs for age-similar controls. Similarly, no significant subretinal OCT findings were seen in the 3 older subjects with the lowest total cones. In contrast, there were subretinal deposits, indistinguishable from drusenoid deposits, in a 62 yr old with 273,000 total cones, the second highest of diabetics and within 95% CIs of controls. No subject had subretinal fluid on OCT.
Conclusions :
Diabetic subjects with retinal thicknesses within normal limits can nevertheless have numerous retinal lesions, visible on OCT B-scans. Retinal vessel remodeling is visible on OCTA but to a lesser extent than with AOSLO. Our findings are inconsistent with early subretinal changes being necessary for low cone densities.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.